HP HP-67

Section 5
Function Keys
The HP-67 has dozens of internal functions that allow you to compute
answers to problems quickly and accurately. Each function operates
the same way, regardless of whether you press the function key
manually or the function is executed as part of a program.
To use any of the keys manually, first ensure that the W/PRGM-
RUN switch wrram M run is set to RUN.
Number Alteration Keys
Besides I, there are four keys provided for altering numbers in the
HP-67. These keys are (i), (ABS), (1), and (FRAC), and you will
find them most useful when performing operations as part of a
program.
Rounding a Number
As you know, when you change display formats with one of the dis-
play control keys ((F1], (5¢1), ENG), or &), the number maintains
its full value to 10 digits multiplied by a two-digit exponent of 10
no matter how many digits you see. When you press the [ prefix
key followed by the (round) key, however, the number that is
in the display becomes the actual number in the calculator. For
example, key in the number of cubic centimeters in one cubic inch,
16.387064 and round it to two decimal places:
Press Display
16.387064 16.387064
=3 2 16.39 Number rounded to two
decimal places in display.
Maintains entire value
internally.
o 16.39 Number rounded to two
decimal places internally.
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